Understand addiction. Almost all drugs are addictive in some manner, even coffee. Generally there are two kinds of addiction: chemical addiction and psychological addiction. Powerful drugs, both legal and illegal, tend to be chemically addictive. Heroin is a powerful chemically addictive illegal drug while nicotine, found in cigarettes, is a similarly powerful legal drug. If somebody is suffering from a drug problem with a chemically addictive drug, understand that it is a disease -- not a part of them. The same is true for alcoholics, for example.